Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The combination of piperacillin and the beta-lactamase inhibitor tazobactam (formerly YTR 830) was studied to determine optimal disk concentrations and dilution testing conditions. In addition, the potency of the combination was compared to that of piperacillin alone. The spectrum of piperacillin was greatly expanded by the addition to tazobactam principally against beta-lactamase producing strains of Haemophilus influenzae, Escherichia coli, Morganella morganii, Proteus vulgaris, Providencia stuartii, Shigella spp., Neisseria gonorrhoeae, and Staphylococcus spp. Tazobactam was active alone against Branhamella catarrhalis (minimum inhibitory concentration [MIC] 50, less than or equal to 1 microgram/ml), gonococci (MIC 50, 0.5-4 micrograms/ml), and N. meningitidis (MIC 50, less than or equal to 1 microgram/ml). Studies with beta-lactamase-producing type strains showed tazobactam to have high affinity for plasmid-mediated enzymes (TEM-1 and 2, SHV-1, HMS-1, and some CARB or OXA types) and not chromosomal beta-lactamases. Piperacillin/tazobactam inhibited 93% of fluoro-quinolone resistant strains at less than or equal to 64/8 micrograms/ml but failed to suppress the growth of 15 strains producing stably depressed cephalosporinases. Comparisons of piperacillin/tazobactam results determined with 100/10-, 100/20-, and 100/30-micrograms disks established the 100/10-micrograms disk as most usable. Among five different MIC combinations the ratio of eight parts piperacillin to one part tazobactam or fixed concentration tests at greater than or equal to 4 micrograms tazobactam/ml were preferred, each producing very low occurrences (less than or equal to 1.6%) of false-resistance or -susceptibility when compared to disk test results. MICs determined by agar and broth microdilution methods were essentially the same. The recommended breakpoints for piperacillin/tazobactam MICs were identical to those now found in the NCCLS susceptibility testing standards with the following exceptions: (1) for tests with H. influenzae and Staphylococcus spp.--susceptible at greater than or equal to 21 mm (MIC less than or equal to 16/2 micrograms/ml) and resistant less than or equal to 20 mm (MIC less or equal to 32/4 micrograms/ml); and (2) all remaining nonspeudomonas isolates would be interpreted by the NCCLS piperacillin enteric bacilli susceptibility criteria. This newer beta-lactamase inhibitor combination appears to be worthy of further in vivo trials guided by these or similar tentative in vitro susceptibility testing parameters.
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PMID:Studies to optimize the in vitro testing of piperacillin combined with tazobactam (YTR 830). 256 Apr 22

The antimicrobial activity of BMY-28100 was tested against approximately 7,000 bacterial pathogens in a multicenter, multiphased collaborative investigation. The BMY-28100 spectrum and antimicrobial potency was most similar to that of cefaclor and superior to that of cephalexin among currently available cephalosporins. Species that had greater than or equal to 90% of clinical strains inhibited by BMY-28100 (less than or equal to 8.0 micrograms/ml) were: Citrobacter diversus, Escherichia coli, Klebsiella spp., Proteus mirabilis, Salmonella spp., Branhamella catarrhalis, Haemophilus influenzae, Neisseria gonorrhoeae, N. meningitidis, methicillin-susceptible Staphylococcus supp., Streptococcus pneumoniae, S. pyogenes, S. agalactiae, S. bovis, serogroup C and G streptococci, Listeria monocytogenes and gm-positive anaerobes. BMY-28100 inhibited 9% more of the 6286 fresh clinical isolates at less than or equal to 8.0 micrograms/ml than cefaclor at the same concentration. BMY-28100 was generally bactericidal, but MICs for some species were markedly increased when an inoculum concentration of 10(7) CFU/ml was used. Strains producing plasmid-mediated beta-lactamases (TEM, OXA, SHV, HMS) were susceptible to BMY-28100, cefaclor, and cefuroxime. BMY-28100 was less active against strains producing chromosomal-mediated beta-lactamases (Types I and IV). BMY-28100 was not hydrolyzed significantly by the tested plasmid-mediated beta-lactamases, but was destroyed by Type I cephalosporinases and Klebsiella K1 enzymes.
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PMID:BMY-28100, a new oral cephalosporin: antimicrobial activity against nearly 7,000 recent clinical isolates, comparative potency with other oral agents, and activity against beta-lactamase producing isolates. 325 89

A rapid, simple assay for screening large numbers of Escherichia coli colonies for production of certain plasmid-mediated beta-lactamases (including TEM-1, TEM-2, HMS-1, SHV-1, OXA-1, PSE-1, PSE-4, and CEP-2) is described. The technique, a modification of the method of Slack et al. for detection of beta-lactamase in limited numbers of Haemophilus influenzae clinical isolates (Lancet ii:906, 1977), uses filter paper impregnated with benzylpenicillin and a pH indicator dye (bromocresol purple) that changes color in the presence of beta-lactamase activity. The test paper is briefly applied to an agar surface containing bacterial colonies which are subsequently scored individually on the paper by color: yellow indicates the presence of beta-lactamase, dark green its absence, and variegation (yellow and dark green) a mixed population. Concordance of the results of this assay with those of replica plating for antibiotic resistance was over 99%. Hundreds of colonies per plate can be scored quickly and remain viable for further evaluation. The assay appears to be useful for studies of the stability of plasmids encoding beta-lactamases and in cloning with vectors such as pBR322 in which insertion of DNA fragments can be detected by inactivation of the beta-lactamase gene. Whenever the assay is to be used, results should always be confirmed initially by another method, such as replica plating, because the test paper assay does not detect three beta-lactamases (OXA-2, OXA-3, and PSE-2) and also would miss intrinsic penicillin resistance.
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PMID:Rapid method for screening large numbers of Escherichia coli colonies for production of plasmid-mediated beta-lactamases. 634 Jun 5